Thermostat with ring-shaped control member

ABSTRACT

A sleek, low-profile wall-mountable thermostat for controlling an HVAC system is described. The thermostat includes a ring-shaped controller that rotates about a central axis, and an optical sensor directed away from the central axis and toward a radially inward-facing surface of the ring-shaped controller so as to accurately detect optical signals indicating controller&#39;s rotational movement.

This application is a continuation of U.S. patent application Ser. No.13/033,573, filed Feb. 23, 2011, which claims priority to U.S. Prov.Ser. No. 61/429,093, filed Dec. 31, 2010 and U.S. Prov. Ser. No.61/415,771, filed Nov. 19, 2010. This application also claims thebenefit of the commonly assigned U.S. Prov. Ser. No. 61/627,996 filedOct. 21, 2011, which is incorporated by reference herein.

FIELD

This patent specification relates to systems, methods, and relatedcomputer program products for the monitoring and control ofenergy-consuming systems or other resource-consuming systems. Moreparticularly, this patent specification relates to a low-profilewall-mountable thermostat having ring-shaped control member surroundinga rounded display.

BACKGROUND

In designing a visually pleasing wall-mounted thermostat, it isdesirable to have a thermostat that has a sleek profile that does notprotrude far from the wall. For enhancing user interface function andaccuracy, it is also desirable for a rotating ring to have a high degreeof sensing accuracy of rotational movement. For example accuracy ofrotational movement is important so that the user can accurately userthe rotating ring for adjusting setting setpoint temperatures and times,navigating menus and selecting options.

It is to be appreciated that although exemplary embodiments arepresented herein for the particular context of HVAC system control,there are a wide variety of other resource usage contexts for which theembodiments are readily applicable including, but not limited to, waterusage, air usage, the usage of other natural resources, and the usage ofother (i.e., non-HVAC-related) forms of energy, as would be apparent tothe skilled artisan in view of the present disclosure. Therefore, suchapplication of the embodiments in such other resource usage contexts isnot outside the scope of the present teachings.

SUMMARY

According to one or more embodiments thermostat for controlling an HVACsystem is described. The thermostat includes: a housing; a processingsystem disposed with in the housing; a rounded electronic displaycoupled to the processing system and mounted on the housing and adaptedto display information to a user; a ring-shaped control member mountedon the housing so as to surround the rounded display and rotate about acentral axis; and an optical sensor mounted within the housing anddirected away from the central axis and toward a radially inward-facingsurface of the ring-shaped control member, so as to detect opticalsignals indicating rotational movement of ring-shaped control member andgenerate electrical signals therefrom, and the processing system beingadapted and configured to detect user input based on the electricalsignals generated by the optical sensor.

According to some embodiments, the radially inward-facing surface of thering-shaped control member is curved and is textured to enhancedetection of optical signals indicating rotational movement. Thethermostat housing can be adapted to be mounted on a wall, andpreferably has a relatively low profile such that it does not protrudefar from the wall. According to some embodiments, the ring-shapedcontrol member is configured to be inwardly pressable by the user alonga direction of the central axis, and together with the rotationalmovement represents the sole physical user inputs to the thermostat.According to some embodiments, the housing is generally disk-like inshape, said display is circular, and the ring-shaped control membergenerally makes up an outer lateral periphery of the disk-like shape.

According to some embodiments a method is described for control of anHVAC system by a thermostat. The thermostat includes a housing, aprocessing system disposed with in the housing, a rounded electronicdisplay coupled to the processing system and mounted on the body andadapted to display information to a user, a ring-shaped control membermounted on the body so as to surround the rounded display and rotateabout a central axis, and an optical sensor mounted within the body anddirected away from the central axis and toward a radially inward-facingsurface of the ring-shaped control member. The method includes:detecting optical signals using the optical sensor indicating rotationalmovement of the radially inward facing surface of the ring-shapedcontrol member; generating electrical signals therefrom; detect userinput using the processing system based on the electrical signalsgenerated by the optical sensor; and displaying information to the useron the rounded electronic display in response to the detected userinput.

It will be appreciated that these systems and methods are novel, as areapplications thereof and many of the components, systems, methods andalgorithms employed and included therein. It should be appreciated thatembodiments of the presently described inventive body of work can beimplemented in numerous ways, including as processes, apparatus,systems, devices, methods, computer readable media, computationalalgorithms, embedded or distributed software and/or as a combinationthereof. Several illustrative embodiments are described below.

BRIEF DESCRIPTION OF THE DRAWINGS

The inventive body of work will be readily understood by referring tothe following detailed description in conjunction with the accompanyingdrawings, in which:

FIG. 1 illustrates an example of a smart home environment within whichone or more of the devices, methods, systems, services, and/or computerprogram products described further herein can be applicable;

FIG. 2 illustrates a network-level view of an extensible devices andservices platform with which the smart home of FIG. 1 can be integrated,according to some embodiments;

FIG. 3 illustrates an abstracted functional view of the extensibledevices and services platform of FIG. 2, according to some embodiments;

FIG. 4 is a schematic diagram of an HVAC system, according to someembodiments;

FIGS. 5A-5D illustrate a thermostat having a visually pleasing, smooth,sleek and rounded exterior appearance while at the same time includingone or more sensors for detecting occupancy and/or users, according tosome embodiments;

FIGS. 6A-6B illustrate exploded front and rear perspective views,respectively, of a thermostat with respect to its two main components,according to some embodiments;

FIGS. 6C-6D illustrate exploded front and rear perspective views,respectively, of a head unit with respect to its primary components,according to some embodiments;

FIGS. 6E-6F illustrate exploded front and rear perspective views,respectively, of a head unit frontal assembly with respect to itsprimary components, according to some embodiments;

FIGS. 6G-6H illustrate exploded front and rear perspective views,respectively, of a back plate unit with respect to its primarycomponents, according to some embodiments;

FIGS. 7A-7B are cross-sectional diagrams of two different designs foroptically sensing rotational movement of a rotating ring of athermostat;

FIGS. 7C-7D are perspective views showing the inner textured surface ofthe rotating ring, according to some embodiments;

FIG. 7E shows the relationship between the optical sensor, texturedsurface of the rotating ring, and central axis of the thermostat,according to some embodiments; and

FIG. 8 shows a multi functional controller that uses the rotating ringto control both an HVAC system and room lighting, according to someembodiments.

DETAILED DESCRIPTION

The subject matter of this patent specification relates to the subjectmatter of the following commonly assigned applications, each of which isincorporated by reference herein: U.S. Ser. No. 13/199,108 filed Aug.17, 2011; U.S. Ser. No. 13/466,026 filed May 7, 2012; and InternationalApplication Ser. No. PCT/US12/00007 filed Jan. 3, 2012. The subjectmatter of this patent specification further relates to the subjectmatter of the commonly assigned U.S. Ser. No. 13/624,881, entitled“Integrating Sensing Systems Into Thermostat Housing In MannersFacilitating Compact And Visually Pleasing Physical CharacteristicsThereof” filed even date herewith, which is incorporated by referenceherein. The subject matter of this patent specification further relatesto the subject matter of the commonly assigned U.S. Ser. No. 13/624,878,entitled “Thermostat With Wiring Terminals Configured for SpatialCompactness and Ease of Wire Installation” filed even date herewith,which is incorporated by reference herein. The above-referenced patentapplications are collectively referenced herein as “the commonlyassigned incorporated applications.”

A detailed description of the inventive body of work is provided herein.While several embodiments are described, it should be understood thatthe inventive body of work is not limited to any one embodiment, butinstead encompasses numerous alternatives, modifications, andequivalents. In addition, while numerous specific details are set forthin the following description in order to provide a thoroughunderstanding of the inventive body of work, some embodiments can bepracticed without some or all of these details. Moreover, for thepurpose of clarity, certain technical material that is known in therelated art has not been described in detail in order to avoidunnecessarily obscuring the inventive body of work.

As used herein the term “HVAC” includes systems providing both heatingand cooling, heating only, cooling only, as well as systems that provideother occupant comfort and/or conditioning functionality such ashumidification, dehumidification and ventilation.

As used herein the terms power “harvesting,” “sharing” and “stealing”when referring to HVAC thermostats all refer to thermostats that aredesigned to derive power from the power transformer through theequipment load without using a direct or common wire source directlyfrom the transformer.

As used herein the term “residential” when referring to an HVAC systemmeans a type of HVAC system that is suitable to heat, cool and/orotherwise condition the interior of a building that is primarily used asa single family dwelling. An example of a cooling system that would beconsidered residential would have a cooling capacity of less than about5 tons of refrigeration (1 ton of refrigeration=12,000 Btu/h).

As used herein the term “light commercial” when referring to an HVACsystem means a type of HVAC system that is suitable to heat, cool and/orotherwise condition the interior of a building that is primarily usedfor commercial purposes, but is of a size and construction that aresidential HVAC system is considered suitable. An example of a coolingsystem that would be considered residential would have a coolingcapacity of less than about 5 tons of refrigeration.

As used herein the term “thermostat” means a device or system forregulating parameters such as temperature and/or humidity within atleast a part of an enclosure. The term “thermostat” may include acontrol unit for a heating and/or cooling system or a component part ofa heater or air conditioner. As used herein the term “thermostat” canalso refer generally to a versatile sensing and control unit (VSCU unit)that is configured and adapted to provide sophisticated, customized,energy-saving HVAC control functionality while at the same time beingvisually appealing, non-intimidating, elegant to behold, anddelightfully easy to use.

FIG. 1 illustrates an example of a smart home environment within whichone or more of the devices, methods, systems, services, and/or computerprogram products described further herein can be applicable. Thedepicted smart home environment includes a structure 150, which caninclude, e.g., a house, office building, garage, or mobile home. It willbe appreciated that devices can also be integrated into a smart homeenvironment that does not include an entire structure 150, such as anapartment, condominium, or office space. Further, the smart homeenvironment can control and/or be coupled to devices outside of theactual structure 150. Indeed, several devices in the smart homeenvironment need not physically be within the structure 150 at all. Forexample, a device controlling a pool heater or irrigation system can belocated outside of the structure 150.

The depicted structure 150 includes a plurality of rooms 152, separatedat least partly from each other via walls 154. The walls 154 can includeinterior walls or exterior walls. Each room can further include a floor156 and a ceiling 158. Devices can be mounted on, integrated with and/orsupported by a wall 154, floor or ceiling.

The smart home depicted in FIG. 1 includes a plurality of devices,including intelligent, multi-sensing, network-connected devices that canintegrate seamlessly with each other and/or with cloud-based serversystems to provide any of a variety of useful smart home objectives.One, more or each of the devices illustrated in the smart homeenvironment and/or in the figure can include one or more sensors, a userinterface, a power supply, a communications component, a modularity unitand intelligent software as described herein. Examples of devices areshown in FIG. 1.

An intelligent, multi-sensing, network-connected thermostat 102 candetect ambient climate characteristics (e.g., temperature and/orhumidity) and control a heating, ventilation and air-conditioning (HVAC)system 103. One or more intelligent, network-connected, multi-sensinghazard detection units 104 can detect the presence of a hazardoussubstance and/or a hazardous condition in the home environment (e.g.,smoke, fire, or carbon monoxide). One or more intelligent,multi-sensing, network-connected entryway interface devices 106, whichcan be termed a “smart doorbell”, can detect a person's approach to ordeparture from a location, control audible functionality, announce aperson's approach or departure via audio or visual means, or controlsettings on a security system (e.g., to activate or deactivate thesecurity system).

Each of a plurality of intelligent, multi-sensing, network-connectedwall light switches 108 can detect ambient lighting conditions, detectroom-occupancy states and control a power and/or dim state of one ormore lights. In some instances, light switches 108 can further oralternatively control a power state or speed of a fan, such as a ceilingfan. Each of a plurality of intelligent, multi-sensing,network-connected wall plug interfaces 110 can detect occupancy of aroom or enclosure and control supply of power to one or more wall plugs(e.g., such that power is not supplied to the plug if nobody is athome). The smart home may further include a plurality of intelligent,multi-sensing, network-connected appliances 112, such as refrigerators,stoves and/or ovens, televisions, washers, dryers, lights (inside and/oroutside the structure 150), stereos, intercom systems, garage-dooropeners, floor fans, ceiling fans, whole-house fans, wall airconditioners, pool heaters 114, irrigation systems 116, security systems(including security system components such as cameras, motion detectorsand window/door sensors), and so forth. While descriptions of FIG. 1 canidentify specific sensors and functionalities associated with specificdevices, it will be appreciated that any of a variety of sensors andfunctionalities (such as those described throughout the specification)can be integrated into the device.

In addition to containing processing and sensing capabilities, each ofthe devices 102, 104, 106, 108, 110, 112, 114 and 116 can be capable ofdata communications and information sharing with any other of thedevices 102, 104, 106, 108, 110, 112, 114 and 116, as well as to anycloud server or any other device that is network-connected anywhere inthe world. The devices can send and receive communications via any of avariety of custom or standard wireless protocols (Wi-Fi, ZigBee,6LoWPAN, etc.) and/or any of a variety of custom or standard wiredprotocols (CAT6 Ethernet, HomePlug, etc.). The wall plug interfaces 110can serve as wireless or wired repeaters, and/or can function as bridgesbetween (i) devices plugged into AC outlets and communicating usingHomeplug or other power line protocol, and (ii) devices that not pluggedinto AC outlets.

For example, a first device can communicate with a second device via awireless router 160. A device can further communicate with remotedevices via a connection to a network, such as the Internet 162. Throughthe Internet 162, the device can communicate with a central server or acloud-computing system 164. The central server or cloud-computing system164 can be associated with a manufacturer, support entity or serviceprovider associated with the device. For one embodiment, a user may beable to contact customer support using a device itself rather thanneeding to use other communication means such as a telephone orInternet-connected computer. Further, software updates can beautomatically sent from the central server or cloud-computing system 164to devices (e.g., when available, when purchased, or at routineintervals).

By virtue of network connectivity, one or more of the smart-home devicesof FIG. 1 can further allow a user to interact with the device even ifthe user is not proximate to the device. For example, a user cancommunicate with a device using a computer (e.g., a desktop computer,laptop computer, or tablet) or other portable electronic device (e.g., asmartphone). A webpage or app can be configured to receivecommunications from the user and control the device based on thecommunications and/or to present information about the device'soperation to the user. For example, the user can view a current setpointtemperature for a device and adjust it using a computer. The user can bein the structure during this remote communication or outside thestructure.

The smart home also can include a variety of non-communicating legacyappliances 140, such as old conventional washer/dryers, refrigerators,and the like which can be controlled, albeit coarsely (ON/OFF), byvirtue of the wall plug interfaces 110. The smart home can furtherinclude a variety of partially communicating legacy appliances 142, suchas IR-controlled wall air conditioners or other IR-controlled devices,which can be controlled by IR signals provided by the hazard detectionunits 104 or the light switches 108.

FIG. 2 illustrates a network-level view of an extensible devices andservices platform with which the smart home of FIG. 1 can be integrated,according to some embodiments. Each of the intelligent,network-connected devices from FIG. 1 can communicate with one or moreremote central servers or cloud computing systems 164. The communicationcan be enabled by establishing connection to the Internet 162 eitherdirectly (for example, using 3G/4G connectivity to a wireless carrier),though a hubbed network (which can be scheme ranging from a simplewireless router, for example, up to and including an intelligent,dedicated whole-home control node), or through any combination thereof.

The central server or cloud-computing system 164 can collect operationdata 202 from the smart home devices. For example, the devices canroutinely transmit operation data or can transmit operation data inspecific instances (e.g., when requesting customer support). The centralserver or cloud-computing architecture 164 can further provide one ormore services 204. The services 204 can include, e.g., software update,customer support, sensor data collection/logging, remote access, remoteor distributed control, or use suggestions (e.g., based on collectedoperation data 204 to improve performance, reduce utility cost, etc.).Data associated with the services 204 can be stored at the centralserver or cloud-computing system 164 and the central server orcloud-computing system 164 can retrieve and transmit the data at anappropriate time (e.g., at regular intervals, upon receiving requestfrom a user, etc.).

One salient feature of the described extensible devices and servicesplatform, as illustrated in FIG. 2, is a processing engines 206, whichcan be concentrated at a single server or distributed among severaldifferent computing entities without limitation. Processing engines 206can include engines configured to receive data from a set of devices(e.g., via the Internet or a hubbed network), to index the data, toanalyze the data and/or to generate statistics based on the analysis oras part of the analysis. The analyzed data can be stored as derived data208. Results of the analysis or statistics can thereafter be transmittedback to a device providing ops data used to derive the results, to otherdevices, to a server providing a webpage to a user of the device, or toother non-device entities. For example, use statistics, use statisticsrelative to use of other devices, use patterns, and/or statisticssummarizing sensor readings can be transmitted. The results orstatistics can be provided via the Internet 162. In this manner,processing engines 206 can be configured and programmed to derive avariety of useful information from the operational data obtained fromthe smart home. A single server can include one or more engines.

The derived data can be highly beneficial at a variety of differentgranularities for a variety of useful purposes, ranging from explicitprogrammed control of the devices on a per-home, per-neighborhood, orper-region basis (for example, demand-response programs for electricalutilities), to the generation of inferential abstractions that canassist on a per-home basis (for example, an inference can be drawn thatthe homeowner has left for vacation and so security detection equipmentcan be put on heightened sensitivity), to the generation of statisticsand associated inferential abstractions that can be used for governmentor charitable purposes. For example, processing engines 206 can generatestatistics about device usage across a population of devices and sendthe statistics to device users, service providers or other entities(e.g., that have requested or may have provided monetary compensationfor the statistics). As specific illustrations, statistics can betransmitted to charities 222, governmental entities 224 (e.g., the Foodand Drug Administration or the Environmental Protection Agency),academic institutions 226 (e.g., university researchers), businesses 228(e.g., providing device warranties or service to related equipment), orutility companies 230. These entities can use the data to form programsto reduce energy usage, to preemptively service faulty equipment, toprepare for high service demands, to track past service performance,etc., or to perform any of a variety of beneficial functions or tasksnow known or hereinafter developed.

FIG. 3 illustrates an abstracted functional view of the extensibledevices and services platform of FIG. 2, with particular reference tothe processing engine 206 as well as the devices of the smart home. Eventhough the devices situated in the smart home will have an endlessvariety of different individual capabilities and limitations, they canall be thought of as sharing common characteristics in that each of themis a data consumer 302 (DC), a data source 304 (DS), a services consumer306 (SC), and a services source 308 (SS). Advantageously, in addition toproviding the essential control information needed for the devices toachieve their local and immediate objectives, the extensible devices andservices platform can also be configured to harness the large amount ofdata that is flowing out of these devices. In addition to enhancing oroptimizing the actual operation of the devices themselves with respectto their immediate functions, the extensible devices and servicesplatform can also be directed to “repurposing” that data in a variety ofautomated, extensible, flexible, and/or scalable ways to achieve avariety of useful objectives. These objectives may be predefined oradaptively identified based on, e.g., usage patterns, device efficiency,and/or user input (e.g., requesting specific functionality).

For example, FIG. 3 shows processing engine 206 as including a number ofparadigms 310. Processing engine 206 can include a managed servicesparadigm 310 a that monitors and manages primary or secondary devicefunctions. The device functions can include ensuring proper operation ofa device given user inputs, estimating that (e.g., and responding to) anintruder is or is attempting to be in a dwelling, detecting a failure ofequipment coupled to the device (e.g., a light bulb having burned out),implementing or otherwise responding to energy demand response events,or alerting a user of a current or predicted future event orcharacteristic. Processing engine 206 can further include anadvertising/communication paradigm 310 b that estimates characteristics(e.g., demographic information), desires and/or products of interest ofa user based on device usage. Services, promotions, products or upgradescan then be offered or automatically provided to the user. Processingengine 206 can further include a social paradigm 310 c that usesinformation from a social network, provides information to a socialnetwork (for example, based on device usage), processes data associatedwith user and/or device interactions with the social network platform.For example, a user's status as reported to their trusted contacts onthe social network could be updated to indicate when they are home basedon light detection, security system inactivation or device usagedetectors. As another example, a user may be able to share device-usagestatistics with other users. Processing engine 206 can include achallenges/rules/compliance/rewards paradigm 310 d that informs a userof challenges, rules, compliance regulations and/or rewards and/or thatuses operation data to determine whether a challenge has been met, arule or regulation has been complied with and/or a reward has beenearned. The challenges, rules or regulations can relate to efforts toconserve energy, to live safely (e.g., reducing exposure to toxins orcarcinogens), to conserve money and/or equipment life, to improvehealth, etc.

Processing engine can integrate or otherwise utilize extrinsicinformation 316 from extrinsic sources to improve the functioning of oneor more processing paradigms. Extrinsic information 316 can be used tointerpret operational data received from a device, to determine acharacteristic of the environment near the device (e.g., outside astructure that the device is enclosed in), to determine services orproducts available to the user, to identify a social network orsocial-network information, to determine contact information of entities(e.g., public-service entities such as an emergency-response team, thepolice or a hospital) near the device, etc., to identify statistical orenvironmental conditions, trends or other information associated with ahome or neighborhood, and so forth.

An extraordinary range and variety of benefits can be brought about by,and fit within the scope of, the described extensible devices andservices platform, ranging from the ordinary to the profound. Thus, inone “ordinary” example, each bedroom of the smart home can be providedwith a smoke/fire/CO alarm that includes an occupancy sensor, whereinthe occupancy sensor is also capable of inferring (e.g., by virtue ofmotion detection, facial recognition, audible sound patterns, etc.)whether the occupant is asleep or awake. If a serious fire event issensed, the remote security/monitoring service or fire department isadvised of how many occupants there are in each bedroom, and whetherthose occupants are still asleep (or immobile) or whether they haveproperly evacuated the bedroom. While this is, of course, a veryadvantageous capability accommodated by the described extensible devicesand services platform, there can be substantially more “profound”examples that can truly illustrate the potential of a larger“intelligence” that can be made available. By way of perhaps a more“profound” example, the same data bedroom occupancy data that is beingused for fire safety can also be “repurposed” by the processing engine206 in the context of a social paradigm of neighborhood childdevelopment and education. Thus, for example, the same bedroom occupancyand motion data discussed in the “ordinary” example can be collected andmade available for processing (properly anonymized) in which the sleeppatterns of schoolchildren in a particular ZIP code can be identifiedand tracked. Localized variations in the sleeping patterns of theschoolchildren may be identified and correlated, for example, todifferent nutrition programs in local schools.

FIG. 4 is a schematic diagram of an HVAC system, according to someembodiments. HVAC system 103 provides heating, cooling, ventilation,and/or air handling for an enclosure, such as structure 150 depicted inFIG. 1. System 103 depicts a forced air type heating and cooling system,although according to other embodiments, other types of HVAC systemscould be used such as radiant heat based systems, heat-pump basedsystems, and others.

For carrying out the heating function, heating coils or elements 442within air handler 440 provide a source of heat using electricity or gasvia line 436. Cool air is drawn from the enclosure via return air duct446 through filter 470, using fan 438 and is heated through heatingcoils or elements 442. The heated air flows back into the enclosure atone or more locations via supply air duct system 452 and supply airregisters such as register 450. In cooling, an outside compressor 430passes a refrigerant gas through a set of heat exchanger coils and thenthrough an expansion valve. The gas then goes through line 432 to thecooling coils or evaporator coils 434 in the air handler 440 where itexpands, cools and cools the air being circulated via fan 438. Ahumidifier 454 may optionally be included in various embodiments thatreturns moisture to the air before it passes through duct system 452.Although not shown in FIG. 4, alternate embodiments of HVAC system 103may have other functionality such as venting air to and from theoutside, one or more dampers to control airflow within the duct system452 and an emergency heating unit. Overall operation of HVAC system 103is selectively actuated by control electronics 412 communicating withthermostat 102 over control wires 448.

FIGS. 5A-5D illustrate a thermostat having a visually pleasing, smooth,sleek and rounded exterior appearance while at the same time includingone or more sensors for detecting occupancy and/or users, according tosome embodiments. FIG. 5A is front view, FIG. 5B is a bottom elevation,FIG. 5C is a right side elevation, and FIG. 5D is prospective view ofthermostat 102. Unlike many prior art thermostats, thermostat 102 has asleek, simple, uncluttered and elegant design that does not detract fromhome decoration, and indeed can serve as a visually pleasing centerpiecefor the immediate location in which it is installed. Moreover, userinteraction with thermostat 102 is facilitated and greatly enhanced overknown conventional thermostats by the design of thermostat 102. Thethermostat 102 includes control circuitry and is electrically connectedto an HVAC system 103, such as is shown in FIGS. 1-4. Thermostat 102 iswall mountable, is circular in shape, and has an outer rotatable ring512 for receiving user input. Thermostat 102 is circular in shape inthat it appears as a generally disk-like circular object when mounted onthe wall. Thermostat 102 has a large convex rounded front face lyinginside the outer ring 512. According to some embodiments, thermostat 102is approximately 80 mm in diameter and protrudes from the wall, whenwall mounted, by 32 mm. The outer rotatable ring 512 allows the user tomake adjustments, such as selecting a new setpoint temperature. Forexample, by rotating the outer ring 512 clockwise, the realtime (i.e.currently active) setpoint temperature can be increased, and by rotatingthe outer ring 512 counter-clockwise, the realtime setpoint temperaturecan be decreased. The front face of the thermostat 102 comprises a clearcover 514 that according to some embodiments is polycarbonate, and aFresnel lens 510 having an outer shape that matches the contours of thecurved outer front face of the thermostat 102. According to someembodiments, the Fresnel lens elements are formed on the interiorsurface of the Fresnel lens piece 510 such that they are not obviouslyvisible by viewing the exterior of the thermostat 102. Behind theFresnel lens is a passive infrared sensor 550 for detecting occupancy,and the Fresnel lens piece 510 is made from a high-density polyethylene(HDPE) that has an infrared transmission range appropriate forsensitivity to human bodies. As shown in FIGS. 5A-5D, the front edge ofrotating ring 512, front face 514 and Fresnel lens 510 are shaped suchthat they together form a, integrated convex rounded front face that hasa common outward arc or spherical shape gently arcing outward.

Although being formed from a single lens-like piece of material such aspolycarbonate, the cover 514 has two different regions or portionsincluding an outer portion 514 o and a central portion 514 i. Accordingto some embodiments, the cover 514 is painted or smoked around the outerportion 514 o, but leaves the central portion 514 i visibly clear so asto facilitate viewing of an electronic display 516 disposedthereunderneath. According to some embodiments, the curved cover 514acts as a lens that tends to magnify the information being displayed inelectronic display 516 to users. According to some embodiments thecentral electronic display 516 is a dot-matrix layout (i.e. individuallyaddressable) such that arbitrary shapes can be generated, rather thanbeing a segmented layout. According to some embodiments, a combinationof dot-matrix layout and segmented layout is employed. According to someembodiments, central display 516 is a backlit color liquid crystaldisplay (LCD). An example of information displayed on the electronicdisplay 516 is illustrated in FIG. 5A, and includes central numerals 520that are representative of a current setpoint temperature. Thethermostat 102 is preferably constructed such that the electronicdisplay 516 is at a fixed orientation and does not rotate with the outerring 512, so that the electronic display 516 remains easily read by theuser. For some embodiments, the cover 514 and Fresnel lens 510 alsoremain at a fixed orientation and do not rotate with the outer ring 512.According to one embodiment in which the diameter of the thermostat 102is about 80 mm, the diameter of the electronic display 516 is about 45mm. According to some embodiments the gently outwardly curved shape ofthe front surface of thermostat 102, which is made up of cover 514,Fresnel lens 510 and the front facing portion of ring 512, is spherical,and matches a sphere having a radius of between 100 mm and 150 mm.According to some embodiments, the radius of the spherical shape of thethermostat front is about 136 mm.

Motion sensing with PIR sensor 550 as well as other techniques can beused in the detection and/or predict of occupancy, as is describedfurther in the commonly assigned U.S. Ser. No. 12/881,430, which isincorporated herein by reference. According to some embodiments,occupancy information is used in generating an effective and efficientscheduled program. A second downwardly-tilted PIR sensor 552 is providedto detect an approaching user. The proximity sensor 552 can be used todetect proximity in the range of about one meter so that the thermostat102 can initiate “waking up” when the user is approaching the thermostatand prior to the user touching the thermostat. Such use of proximitysensing is useful for enhancing the user experience by being “ready” forinteraction as soon as, or very soon after the user is ready to interactwith the thermostat. Further, the wake-up-on-proximity functionalityalso allows for energy savings within the thermostat by “sleeping” whenno user interaction is taking place our about to take place.

According to some embodiments, for the combined purposes of inspiringuser confidence and further promoting visual and functional elegance,the thermostat 102 is controlled by only two types of user input, thefirst being a rotation of the outer ring 512 as shown in FIG. 5A(referenced hereafter as a “rotate ring” or “ring rotation” input), andthe second being an inward push on head unit 540 until an audible and/ortactile “click” occurs (referenced hereafter as an “inward click” orsimply “click” input). For such embodiments, the head unit 540 is anassembly that includes all of the outer ring 512, cover 514, electronicdisplay 516, and the Fresnel lens 510. When pressed inwardly by theuser, the head unit 540 travels inwardly by a small amount, such as 0.5mm, against an interior metallic dome switch (not shown), and thenspringably travels back outwardly by that same amount when the inwardpressure is released, providing a satisfying tactile “click” sensationto the user's hand, along with a corresponding gentle audible clickingsound. Thus, for the embodiment of FIGS. 5A-5D, an inward click can beachieved by direct pressing on the outer ring 512 itself, or by indirectpressing of the outer ring by virtue of providing inward pressure on thecover 514, lens 510, or by various combinations thereof. For otherembodiments, the thermostat 102 can be mechanically configured such thatonly the outer ring 512 travels inwardly for the inward click input,while the cover 514 and lens 510 remain motionless. It is to beappreciated that a variety of different selections and combinations ofthe particular mechanical elements that will travel inwardly to achievethe “inward click” input are within the scope of the present teachings,whether it be the outer ring 512 itself, some part of the cover 514, orsome combination thereof. However, it has been found particularlyadvantageous to provide the user with an ability to quickly go back andforth between registering “ring rotations” and “inward clicks” with asingle hand and with minimal amount of time and effort involved, and sothe ability to provide an inward click directly by pressing the outerring 512 has been found particularly advantageous, since the user'sfingers do not need to be lifted out of contact with the device, or slidalong its surface, in order to go between ring rotations and inwardclicks. Moreover, by virtue of the strategic placement of the electronicdisplay 516 centrally inside the rotatable ring 512, a further advantageis provided in that the user can naturally focus their attention on theelectronic display throughout the input process, right in the middle ofwhere their hand is performing its functions. The combination ofintuitive outer ring rotation, especially as applied to (but not limitedto) the changing of a thermostat's setpoint temperature, convenientlyfolded together with the satisfying physical sensation of inwardclicking, together with accommodating natural focus on the electronicdisplay in the central midst of their fingers' activity, addssignificantly to an intuitive, seamless, and downright fun userexperience. Further descriptions of advantageous mechanicaluser-interfaces and related designs, which are employed according tosome embodiments, can be found in U.S. Ser. No. 13/033,573, U.S. Ser.No. 29/386,021, and U.S. Ser. No. 13/199,108, all of which areincorporated herein by reference.

FIGS. 5B and 5C are bottom and right side elevation views of thethermostat 102, which has been found to provide a particularly pleasingand adaptable visual appearance when viewed against a variety ofdifferent wall colors and wall textures in a variety of different homeenvironments and home settings. While the thermostat itself willfunctionally adapt to the user's schedule as described herein and in oneor more of the commonly assigned incorporated applications, supra, theouter shape is specially configured to convey a “chameleon” quality orcharacteristic such that the overall device appears to naturally blendin, in a visual and decorative sense, with many of the most common wallcolors and wall textures found in home and business environments, atleast in part because it will appear to assume the surrounding colorsand even textures when viewed from many different angles.

According to some embodiments, the thermostat 102 includes a processingsystem 560, display driver 564 and a wireless communications system 566.The processing system 560 is adapted to cause the display driver 564 anddisplay 516 to display information to the user, and to receiver userinput via the rotatable ring 512. The processing system 560, accordingto some embodiments, is capable of carrying out the governance of theoperation of thermostat 102 including various user interface features.The processing system 560 is further programmed and configured to carryout other operations as described further hereinbelow and/or in otherones of the commonly assigned incorporated applications. For example,processing system 560 is further programmed and configured to maintainand update a thermodynamic model for the enclosure in which the HVACsystem is installed, such as described in U.S. Ser. No. 12/881,463, andin International Patent App. No. PCT/US11/51579, both of which areincorporated herein by reference. According to some embodiments, thewireless communications system 566 is used to communicate with devicessuch as personal computers and/or other thermostats or HVAC systemcomponents, which can be peer-to-peer communications, communicationsthrough one or more servers located on a private network, or and/orcommunications through a cloud-based service.

According to some embodiments, for ease of installation, configurationand/or upgrading, especially by a non-expert installer such as a user,the thermostat 102 includes a head unit 540 and a backplate (or walldock) 542. As is described hereinabove, thermostat 102 is wall mountedand has circular in shape and has an outer rotatable ring 512 forreceiving user input. Head unit 540 of thermostat 102 is slidablymountable onto back plate 542 and slidably detachable therefrom.According to some embodiments the connection of the head unit 540 tobackplate 542 can be accomplished using magnets, bayonet, latches andcatches, tabs or ribs with matching indentations, or simply friction onmating portions of the head unit 540 and backplate 542. Also shown inFIG. 5A is a rechargeable battery 522 that is recharged using rechargingcircuitry 524 that uses power from backplate that is either obtained viapower harvesting (also referred to as power stealing and/or powersharing) from the HVAC system control circuit(s) or from a common wire,if available, as described in further detail in co-pending patentapplication U.S. Ser. Nos. 13/034,674, and 13/034,678, which areincorporated by reference herein. According to some embodiments,rechargeable battery 522 is a single cell lithium-ion, or alithium-polymer battery.

FIGS. 6A-6B illustrate exploded front and rear perspective views,respectively, of the thermostat 102 with respect to its two maincomponents, which are the head unit 540 and the backplate 542. Furthertechnical and/or functional descriptions of various ones of theelectrical and mechanical components illustrated hereinbelow can befound in one or more of the commonly assigned applications, such as U.S.Ser. No. 13/199,108, incorporated herein by reference. In the drawingsshown herein, the “z” direction is outward from the wall, the “y”direction is the toe-to-head direction relative to a walk-up user, andthe “x” direction is the user's left-to-right direction.

FIGS. 6C-6D illustrate exploded front and rear perspective views,respectively, of the head unit 540 with respect to its primarycomponents. Head unit 540 includes, back cover 636, bottom frame 634,battery assembly 632, the outer ring 512 (which is manipulated for ringrotations), head unit frontal assembly 630, front lens 514, and Fresnellens 510. Electrical components on the head unit frontal assembly 630can connect to electrical components on the back plate 542 by virtue ofribbon cables and/or other plug type electrical connectors on back cover636. Head unit frontal assembly 630 is secured to head unit back cover636 and bottom frame 634 via four bosses. The outer ring 512 is therebyheld between a bearing surface on the head unit top frame 652 (shown inFIGS. 6E and 6F, infra) and bearing surfaces on the bottom frame 634. Inparticular motion of the ring 512 in z direction is constrained by flatbearing surfaces on the top frame 652 and bottom frame 634, while motionof the ring in x and y directions are constrained by circular roundedsurfaces on the bottom frame 634. According to some embodiments, thebearing surfaces of the bottom frame 634 and/or the top frame 652 aregreased and/or otherwise lubricated to both smooth and dampen rotationalmovement for ring 512. Attached to top frame 652 is the head unitprinted circuit board (PCB) 654 on which much of the head unit circuitryis mounted including some or all of processing system 560, displaydriver 564, wireless communication system 566 and battery rechargingcircuitry 524 as shown and described with respect to FIG. 5A, as well asone or more additional memory storage components. According to someembodiments, circuitry and components are mounted on both sides of PCB654. A shielding can 656 (visible in FIG. 6D) surrounds most or all ofthe head unit circuitry and components on PCB 654 and serves to shieldthe circuitry and components from electromagnetic interference. Althoughnot visible, according to some embodiments, shielding can 656 surroundscircuitry and components on both sides of PCB 654.

Battery assembly 632 includes a rechargeable Lithium-Ion battery 522,which for one preferred embodiment has a nominal voltage of 3.7 voltsand a nominal capacity of 560 mAh. To extend battery life, however, thebattery 522 is normally not charged beyond 450 mAh by the thermostatbattery charging circuitry. Moreover, although the battery 522 is ratedto be capable of being charged to 4.2 volts, the thermostat batterycharging circuitry normally does not charge it beyond 3.95 volts.Battery assembly 632 also includes connecting wires 666, and a batterymounting film 664 that is attached to battery 522 using a strongadhesive and to the rear shielding can 656 of head unit PCB 654 using arelatively weaker adhesive. By using a weaker adhesive to mount the film664 of battery assembly 632 to shielding can 656 of the PCB 654,subsequent replacement of battery assembly 632 (including battery 522)is facilitated. According to some embodiments, the battery assembly 632is user-replaceable.

FIGS. 6E-6F illustrate exploded front and rear perspective views,respectively, of the head unit frontal assembly 630 with respect to itsprimary components. Head unit frontal assembly 630 comprises a head unittop frame 652, head unit PCB 654, and LCD module 662. Daughter board 660connects to the head unit PCB 654 and includes an optical fingernavigation (OFN) module that is configured and positioned to senserotation of the outer ring 512. The OFN module is directed radiallyoutwardly (that is, perpendicular to the z-axis and away from the centerof the thermostat). The OFN module uses methods analogous to theoperation of optical computer mice to sense the movement of a texturedsurface on an inner face of the outer ring 512. Notably, the OFN moduleis one of the very few sensors that is controlled by the relativelypower-intensive head unit microprocessor rather than the relativelylow-power back plate microprocessor. This is achievable withoutexcessive power drain implications because the head unit microprocessorwill invariably be awake already when the user is manually turning thedial, so there is no excessive wake-up power drain anyway.Advantageously, very fast response can also be provided by the head unitmicroprocessor. Also visible in FIGS. 6E and 6F is Fresnel lens 510 thatoperates in conjunction with two PIR motion sensors mounted on PIR board650. Two or more temperature sensors are also located in the head unit540 and cooperate to acquire reliable and accurate room temperaturedata. One of the temperature sensors is located on daughter board 660and the other is mounted on the head unit PCB 654.

FIGS. 6G-6H illustrate exploded front and rear perspective views,respectively, of the back plate unit 542 with respect to its primarycomponents, according to some embodiments. Back plate unit 542 comprisesa back plate rear plate 682, a back plate circuit board 680, and a backplate cover 670. Visible in FIG. 6G are the HVAC wire connectors 684that include integrated mechanical wire insertion sensing circuitry, andrelatively large capacitors 686 that are used by part of the powerstealing circuitry that is mounted on the back plate circuit board 680.According to some embodiments, backplate 542 includes electronics and atemperature/humidity sensor in housing. Wire connectors 684 are providedto allow for connection to HVAC system wires, which pass though thelarge central circular opening 690, which is visible in each of thebackplate primary components. Also visible in each of the backplateprimary components are two mounting holes 692 and 694 for use in fixingthe backplate to the wall. The single top wall-mounting hole 692 onbackplate has been found to allow for self-leveling during installation,thereby further enhancing the ease of a non-expert installation of thethermostat 102. Also visible in FIGS. 6G and 6H are bubble level 672 andholder 674 for further facilitating user-installability of thethermostat 102.

FIGS. 7A-7B are cross-sectional diagrams of two different designs foroptically sensing rotational movement of a rotating ring of athermostat. FIG. 7A represents a design of a thermostat 780, which makesuse of an optical sensor 774 directed towards the wall, when thermostat780 is wall mounted. For further details of an example of such a design,see, U.S. patent application Ser. No. 13/466,026 filed on May 7, 2012,which is incorporated by reference herein. A rotating ring 772 rotatablyslides on a bottom frame 784. The optical sensor 774 is mounted on acircuit board 782 and is directed toward the wall (in the negativez-direction) on a textured surface 770 of ring 772. Based on movementsdetected by the optical sensor 774 of the textured surface 770 or ring772 rotational movement of ring 772 can be determined. Note that in thedesign represented in FIG. 7A, the optical sensor is directed axially(that is, in a direction parallel to the central axis of the rotatingring), and towards a textured surface on the ring that is parallel tothe wall. The resulting distance h′ is shown that is measured from thecircuit board 782 to the bottom frame 787.

FIG. 7B is a cross-section showing an outwardly radially directedoptical sensor for sensing ring rotational movement, according to someembodiments. In FIG. 7B, rotating ring slidably rotates on bottom frame634. The optical sensor 712 is mounted on a daughter board 660 and haselectrical connections, such as conductors 724 and 726 to head unit PCB654. The processor on PCB 654 is programmed to interpret the electricalsignals from the optical sensor 712 and determine therefrom rotationalmovement of the ring 512.

The optical sensor 712 is directed radially outwardly (that is, in aradial direction outwards from the central axis of thermostat 102 andring 512, which is parallel to the wall when thermostat 102 is wallmounted) towards a textured surface 720 on a curved inner surface ofring 512. According to some embodiments, the optical sensor 712, is anoptical finger navigation (OFN) module, such as known for use innavigation on some smart phones, which has been found to providesuitable accuracy in detecting movement of the textured surface 720 onan inner surface of ring 512. According to other embodiments, othertypes of suitable optical sensors, such as are known for use in opticalmouse pointers, can be used. By mounting the optical sensor 712 suchthat it is directly outwardly radially to detect ring movements on aninner surface 720 of the ring 512, a dimension h between the head unitPCB 654 and bottom frame 634 can be achieved with is significantlysmaller than the dimension h′ shown in the design represented in FIG.7A. A lower dimension h is significant as it allows for enhanced overallsleekness of design and lower profile and lower overall elevation. Whenwall mounted, a thermostat having a lower profile will protrude from thewall less and therefore is more elegant, modern and visually pleasing aswell as less likely to be inadvertently bumped and possibly damaged as aresult. According to some embodiments, the thermostat employing theoutwardly radially directed optical sensor such as shown in FIG. 7Bprotrudes from the wall when wall mounted less than 35 mm. According tosome embodiments, the thermostat protrudes from the wall a total of 32mm. An additional advantage of the design shown FIG. 7B over the onerepresented in FIG. 7A is that the shape and structure of the ring 512is both easier to manufacture, and is more structurally robust than aring such as ring 772 that has a substantial surface parallel to thewall. Such qualities can both lower manufacturing cost as well asimprove overall fit and finish of the end product.

FIGS. 7C-7D are perspective views showing the inner textured surface ofthe rotating ring, according to some embodiments. In FIG. 7C the ring512 is shown in relationship to the entire thermostat 102. The texturedsurface 720 is shown on the curved inner surface of both the frontperspective view of FIG. 7C and the rear perspective view of FIG. 7D.

FIG. 7E shows the relationship between the optical sensor 712, texturedsurface 720 of rotating ring 512, and central axis 730 of the thermostat102, according to some embodiments. As can be seen the textured surface720 and the optical sensor 712 are mounted very close to the outmostperiphery 732 of the thermostat 102. In other words, the radial distancer from the central axis 730 to the textured surface 720 is close to theradial distance r′ from the central axis to the outer periphery 732 ofring 512. In the design shown, for example, the ratio of r/r′ is greaterthan 90 percent. According to some embodiments the ratio of r/r′ ispreferably greater than 75 percent. By positioning the optical sensor712 to sense ring motion near the outer edge of the rotating ring 512 isadvantageous over a more central location, such as designs in which asensor is directly inwardly towards a rotating surface relatively closeto the central rotating axis, because of increased sensitivity todetection motion. For a given amount of rotational displacement of therotating ring, an outward positioned sensor will view a larger length ofmoving material than would a more centrally positioned sensor.Furthermore, the design shown herein is also provides an additionaladvantage over designs with a central rotating post in that the sensingsurface, that is surface 720 on ring 512 is very close the sameelevation from the wall (in the z-direction) from the user's hand as theuser grasps the ring 512. Additionally, the design shown hereincompletely eliminates the need for any central post or other centralrotating member. Rather in the design shown herein, the central area ofthe thermostat 102 is unobstructed by central rotating pieces and thusallows for relatively compact placement and positioning of the variousthermostat components.

Although the outward radially directed optical sensor for control ringmovements has been thus far described with respect to a thermostat,according to some embodiments the concepts and techniques describedherein can be used in a number of other devices for which a combinationof accurate user input detection and a sleek low profile visuallypleasing exterior design is important. Examples include rotating dialsand/or rotating controllers for use with many of the devices andappliance shown and/or described with respect to FIG. 1, including:rotating dials and/or rotating controllers used on appliances (ovens,microwaves, extractor fans, washers, dryers, dishwashers, blenders,coffee makers, wall air conditioners); rotating dials and/or rotatingcontrollers on other home/residential equipment (pool heater controls,irrigation controls, volume control on intercom systems); rotating dialsand/or rotating controllers on light switches (dimmers or selectors);and rotating dials and/or rotating controllers on home entertainmentdevices (e.g. volume for stereos, televisions). For example, FIG. 8shows a multi functional controller 802 that uses the rotating ring 812to control both an HVAC system 103 and room lighting 810. According tosome embodiments, the controller 802 can be retrofitable to replace anexisting light switch, and the control ring 812 serves in one mode as athermostat controller for HVAC system 103 and in another mode as a lightdimmer switch for room lighting 810. It will be appreciated that therotating ring controller as described herein can be used for othercombinations of devices, such as those shown and described with respectto FIG. 1.

Various modifications may be made without departing from the spirit andscope of the invention. It is to be further appreciated that the termthermostat, as used hereinabove and hereinbelow, can include thermostatshaving direct control wires to an HVAC system, and can further includethermostats that do not connect directly with the HVAC system, but thatsense an ambient temperature at one location in an enclosure andcooperatively communicate by wired or wireless data connections with aseparate thermostat unit located elsewhere in the enclosure, wherein theseparate thermostat unit does have direct control wires to the HVACsystem. Accordingly, the invention is not limited to the above-describedembodiments, but instead is defined by the appended claims in light oftheir full scope of equivalents.

What is claimed is:
 1. A thermostat for controlling an HVAC systemcomprising: a housing; a processing system disposed with in the housing;a rounded electronic display coupled to the processing system andmounted on the housing and adapted to display information to a user; aring-shaped control member mounted on the housing so as to surround therounded display and rotate about a central axis, the ring-shaped controlmember being configured to be inwardly pressable by the user along adirection of the central axis; and an optical sensor mounted within thehousing and directed away from the central axis and toward a radiallyinward-facing surface of the ring-shaped control member, so as to detectoptical signals indicating rotational movement of the ring-shapedcontrol member and generate electrical signals therefrom, wherein theprocessing system is adapted and configured to detect user input basedon the electrical signals generated by the optical sensor.
 2. Athermostat according to claim 1 wherein the radially inward-facingsurface of the ring-shaped control member is curved and is textured toenhance detection of the optical signals indicating rotational movement.3. A thermostat according to claim 1 wherein the thermostat housing isadapted to be mounted on a wall.
 4. A thermostat according to claim 3wherein the thermostat is dimensioned such that when mounted on thewall, the thermostat protrudes from the wall no more than 35millimeters.
 5. A thermostat according to claim 4 wherein the thermostatis dimensioned such that when mounted on the wall, the thermostatprotrudes from the wall no more than 32 millimeters.
 6. A thermostataccording to claim 1 wherein the optical sensor is an optical fingernavigation module.
 7. A thermostat according to claim 1 wherein a ratioof (1) a radial distance between the central axis and the inward-facingsurface of the ring-shaped control member and (2) a radial distancebetween the central axis and an outmost periphery of the ring-shapedcontrol member is not less than 75 percent.
 8. A thermostat according toclaim 1 wherein a ratio of (1) a radial distance between the centralaxis and the inward-facing surface of the ring-shaped control member and(2) a radial distance between the central axis and an outmost peripheryof the ring-shaped control member is not less than 90 percent.
 9. Athermostat according to claim 1 wherein the inward-facing surface of thering-shaped control member is parallel to the central axis.
 10. Athermostat according to claim 1 wherein the housing is generallydisk-like in shape, said display is circular, and wherein thering-shaped control member generally makes up an outer lateral peripheryof said disk-like shape.
 11. A thermostat according to claim 1 whereinsaid rotational movement and inward pressings of the ring-shaped controlmember represent sole physical user inputs to said thermostat.
 12. Athermostat for controlling an HVAC system comprising: a housingincluding a head unit and a backplate, the backplate being configured tobe mounted on a wall and the head unit being configured to be removablymounted to the backplate; a processing system disposed with in the headunit; a rounded electronic display coupled to the processing system andmounted on the head unit and adapted to display information to a user; aring-shaped control member rotatably mounted on the head unit so as tosurround the rounded display, to rotatable about a central axis and tobe inwardly pressable in a direction parallel to the central axis; andan optical sensor mounted within the head unit and directed away fromthe central axis and toward a curved radially inward-facing surface ofthe ring-shaped control member, so as to detect optical signalsindicating rotational movement of the ring-shaped control member andgenerate electrical signals therefrom, wherein the processing system isadapted and configured to detect user input based on the electricalsignals generated by the optical sensor.
 13. A thermostat according toclaim 12 wherein the thermostat is generally disk-like in shape anddimensioned such that when mounted on the wall, the thermostat protrudesfrom the wall no more than 35 millimeters, and the ring-shaped controlmember has a solid smooth metallic outwardly facing surface visible toand touchable by the user that generally makes up an outer lateralperiphery of said disk-like shape.
 14. A thermostat according toaccording to claim 13 wherein the outwardly facing surface of thering-shaped control member is outwardly curved so as to bulge in aradially outward direction from the central axis.